🔍 Key Concepts

• Study the gas flow path through the boiler: furnace, generating bank, superheater, economizer, and any air‑side heat exchangers. • Recall that a retractable sootblower is a small, movable cleaning device, while superheaters and air heaters are large, fixed heat‑transfer sections. • Know the difference between an integral/interdeck superheater (within the main boiler gas path), a separately fired superheater (its own furnace), and a regenerative air heater (transfers heat from flue gas to incoming air).

💭 Think About

• Look at where the arrows show air and gas entering and leaving. Does this device act on steam, flue gas, or combustion air? • Ask yourself: Is there a separate furnace or firing arrangement just for superheating, or is everything contained in one main furnace and convection pass? • Does the illustrated section seem like a rotating or cycling heat‑storage unit for air, or a fixed tube bank in the gas path carrying steam/water?

✅ Before You Answer

• Identify whether the working fluid in the highlighted area is steam/water or air. That immediately narrows the choices. • Check if the superheating surfaces are located within the main boiler setting (integral/interdeck) or if there is a clearly separate fired chamber (separately fired). • Verify whether any part of the illustration shows a small lance-type device entering tube banks (typical of a retractable sootblower) versus large banks of tubes or elements.