Flue-gas removal method Which installation typically uses an induced-draft (I.D.) fan to remove flue gases from the furnace or boiler?

Introduction / Context:Draft systems move combustion products from the furnace to the stack. Induced-draft (I.D.) fans pull gases, maintaining a slight negative pressure at the furnace exit. The choice between natural draft and I.D. fans depends on pressure drops, emission controls, and heat-recovery equipment downstream.

Given Data / Assumptions:

• High-pressure boilers possess significant gas-side pressure drops across economisers, superheaters, and particulate controls.
• Traditional coke ovens and beehive ovens historically relied on natural draft or simple draft systems.
• Blast furnace stoves are pressure-balanced with process gas systems and may not require classic I.D. arrangements like boilers.

Concept / Approach:Where high resistance exists in the gas path, an I.D. fan is standard to ensure proper evacuation and control of furnace/boiler pressure. Modern high-pressure boilers almost universally employ I.D. fans (often paired with forced-draft F.D. fans) to manage draft and emissions equipment pressure drop.

Step-by-Step Solution:

Verification / Alternative check:Boiler P&IDs show I.D. fans downstream of economisers/APC devices maintaining negative furnace pressure.

Why Other Options Are Wrong:

• Coke oven / Beehive: Historically natural or simpler draft; not typical I.D. fan installations.
• Blast furnace stoves: Operate within the blast furnace gas system; not the archetypal I.D.-fan example.

Common Pitfalls:Confusing positive pressure firing with the presence of I.D. fans; many systems mix both F.D. and I.D., but high-pressure boilers are the canonical case.

Final Answer:High-pressure boiler.