In a steaming boiler, higher than normal...

In a steaming boiler, higher than normal...

Question 1 of 270705eccefa0bacbc34ba4d46e63

In a steaming boiler, higher than normal stack gas temperature can be caused by __________.

Question 1 of 27070

Q

In a steaming boiler, higher than normal stack gas temperature can be caused by __________.

🔍 Key Concepts

• combustion efficiency in boilers and how it affects stack gas temperature • difference between excess air and insufficient air in fuel combustion • how burn time/location of flame in the furnace influences heat transfer to boiler tubes

💭 Think About

• Think about what happens to the flame and heat transfer if the fuel is still burning as the gases are already moving toward the uptake/stack. • Which condition would cause more heat to leave with the exhaust instead of being absorbed by the water/steam in the boiler? • For each choice, ask yourself: does this make combustion more complete inside the furnace, or does it push burning farther toward the stack?

✅ Before You Answer

• For each option, decide whether it would make the flame hotter and shorter inside the furnace or cooler/longer and shifted toward the uptake. • Consider how too much excess air versus too little excess air changes flame temperature and where burning finishes. • Verify which condition is most likely to cause afterburning in the upper furnace or uptake, raising stack gas temperature.