Waste heat recovery

Generating steam from flue gases

Generating steam is a profitable way of reusing high-temperature waste heat. This can reduce the load on process steam boilers and allows you to save fuel or use the extra capacity for electricity generation.

Alfa Laval Aalborg offers a series of highly efficient waste heat recovery boilers that extract heat from hot flue gases and generate steam or hot water.

A boiler is easily added to your flue gas stream and recovers heat that would normally be released into the air through a chimney.

There are many possibilities to profit from recovered heat. It can be used for process heating, electricity generation or for district heating..


In this example an Alfa Laval Aalborg waste steam boiler generates steam from flue gases.

The diagrams show the payback time for different amounts of recovered energy, from 2 to 15 MW.


Adding an Alfa Laval Aalborg waste heat recovery boiler helps you make use of energy in your fuel gases.


  • 8,400 operating hours per year
  • Automatic cleaning system removes ash during operation
  • Total installation cost estimate based on experience
  • Exit temperature of the flue gas assumed to be well above the sulphur dew point

Recovering heat from flue gases

Payback period for flue gas heat recovery system for different stem prices

Process heating

Electricity generation