🔍 Key Concepts

• Soot formation on heating surfaces and how it affects heat transfer efficiency • The difference in gas flow paths and heating surfaces between fire-tube and water-tube boilers • Which boiler designs have gas-side tube banks exposed to flue gases that tend to accumulate soot

💭 Think About

• Ask yourself: In which boiler type do hot combustion gases pass over or through tubes where soot can easily deposit and need to be blown off? • Consider which boiler types rely on electrical heating versus combustion gases, and whether soot is even produced in that design. • Between fire-tube and water-tube boilers, which configuration places more small-diameter tubes directly in the path of high-velocity flue gas, making soot blowing important?

✅ Before You Answer

• Verify which options actually produce flue gas and soot (not just heat without combustion). • Identify which boiler type has extensive external gas-side surfaces that can foul with soot and require routine cleaning. • Check whether both natural-circulation and forced-circulation affect the need for soot blowers, or if the key factor is the gas-side heating surface arrangement.