Boiler & Energy Systems

Boiler Flue Gas & Economizer Applications

Boiler economizers and flue gas heat recovery that lower stack temperature and reduce fuel consumption.

The challenge

Boilers and thermal oil heaters commonly discharge flue gas well above the temperature needed for safe draught. Every degree sent up the stack is fuel already paid for and lost, and many plants have no recovery stage at all.

How Qingli solves it

  • Boiler economizers recover flue gas heat into feedwater or a secondary loop.
  • Tubular / seamless steel tube exchangers tolerate higher gas temperatures and pressures than compact plate designs.
  • Material selection accounts for condensation and corrosion risk at the cold end, which is where economizer projects most often fail.
  • Boiler Economizer & Waste Heat Recovery Unit
  • Tubular Heat Exchanger
  • Finned Tube Radiator

What we need from you

Fuel type, flue gas flow and temperature, feedwater temperature, allowable gas side pressure drop, and space available near the stack.

Design note

We set the cold-end temperature deliberately: recovering too much heat can push the gas below its acid dew point and cause corrosion. A sized proposal balances efficiency against service life.

Talk to an Engineer

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