Economizer Coils

Product Description

What Are Economizer Coils?

Economizer coils are tubular heat exchangers located in the flue gas path (after combustion but before exhaust). They preheat the boiler feedwater using the otherwise wasted heat from the flue gases.

Purpose of Economizer Coils:

• Increase boiler efficiency (by 3to10%)

• Reduce fuel consumption

• Lower flue gas temperature

• Reduce operating costs

• Minimize environmental emissions (like CO)

Construction:

• Material: Carbon steel, alloy steel, or stainless steel (depends on flue gas conditions)

• Tube shape: Bare or finned tubes (fins increase surface area and heat transfer)

• Arrangement: Horizontal or vertical, depending on boiler design

Working Principle:

1. Hot flue gases from the boiler pass over the economizer coils.

2. Cooler feedwater flows inside the coils.

3. Heat transfers from gas to water.

4. Water enters the boiler at a higher temperature, reducing fuel needed for steam generation.

Applications:

• Power plants (coal, gas, biomass)

• Industrial steam boilers

• Heat recovery steam generators (HRSGs)

• Marine boilers

• Common Issues:

  • Fouling/soot accumulation (reduces heat transfer)

  • Corrosion (from acidic flue gases)

  • Leakage (due to thermal stress or corrosion)

  • Tube rupture (from overheating or pressure imbalance)

  • Maintenance Tips:

    • Regular cleaning (soot blowers or manual)

    • Inspection for corrosion and scaling

    • Water chemistry control

    • Periodic non-destructive testing (NDT)