Aalborg AV-6N

Aalborg AV-6N is a robust and highly efficient boiler with gilled water tubes which is designed to improve a plant’s overall efficiency by maximizing exhaust gas heat recovery. It is intended for steam and/or hot water production.

AV6N boilers 640x360

High efficiency; less CO2 emissions

  • Natural circulation; high availability, low operational and maintenance costs
  • Compact heating surface, optimisable for different applications
  • Small water volume inside the boiler allows it to respond quickly to load changes
  • Freedom of scope; shop-assembled, or with maximised scope for local outsourcing (e.g., insulations, platforms, inter-connecting pipes etc.)
  • Tailor-made for specific requirements

Aalborg AV-6N boiler is constructed to recover heat from diesel engines, gas engines or other sources.

The boiler’s compact and flexible design, which makes it easy to install, also allows cleaning during operation, which minimizes engine shutdowns and increases plant availability.

Natural circulation is used in the standard steam configuration with resulting advantages for reliability, safety and energy efficiency, although traditional forced-circulation models are available if specifically requested.

Designed with extended heating surface, Aalborg AV-6N is compact and cost-effective. The possibility of cleaning during operation minimises the need for engine shutdowns and increases the overall plant availability. 

Design data

  • Engine output: No limit, depending on engine
  • Engine fuel type: Light oil, liquid biofuel, heavy fuel oil, natural gas
  • Exhaust gas flow: No limits
  • Exhaust gas temp.:Standard up to 530 ºC
  • Operating steam/water pressure: Typically 5-30 bar(g), max. 65 bar(g)
  • Steam/water temperature:Standard up to 400 ºC
  • Natural circulation as standard - forced on special demand
  • Pinch point: Typical 15 - 20 ºC 

How it works

Unique boiler construction

A unique supporting arrangement without endplates - enhanced by computerised analyses - ensures a vibration and thermal stress-free boiler structure sustaining even the most demanding operational conditions of engine-based heat recovery applications.

Reliable natural circulation

As a standard for steam applications, Alfa Laval Aalborg offers reliable natural circulation solutions without the need of circulation pumps providing the following advantages:

  • Reliability
  • Minimised risk of soot fires
  • Less power consumption
  • Cost effectiveness
  • Fast site installation
  • Reduced foundation work and minimized piping and cabling
  • Small footprint

Traditional forced circulation boilers are also available.

Easy to clean

The tube arrangement of the AV-6N heating surface ensures easy maintenance and service. AV-6N boilers can be cleaned during operation reducing the need for engine shut-down. In addition to standard high-efficient steam soot blowers, an air-type can also be applied.

Hot-water heating for free

The AV-6H exhaust gas boiler is a water tube boiler for heat recovery, typically after gas engine. The boiler comes in a horisontal layout and compact workshop assembled module. It is easy and fast to install while allowing maximized access for convenient maintenance and service.

  • High-efficient counterflow design for heating of hot water
  • Proven design to ensure effective and fast cleaning of condensed lube oil residuals (in gas engine application)
  • Compact and flexible layout with integrated walkable service area
  • Low operational weight
  • Minimized gas pockets


Selected references

Sundt RICE power plant, Arizona

Plant owner Tucson Electric Power (TEP) is able to take advantage of increased energy efficiency thanks to an investment in two Alfa Laval Aalborg heat recovery steam generators (HRSG).

8077 Sundt RICE 640x360

Lucky Cement Limited, Pakistan

One of Pakistan’s largest cement manufacturers captures excess heat from the engine exhaust gas with 11 Aalborg AV­6N WHR boilers.

Lucky cement 640x360

Cengiz Enerji, Turkey

By upgrading the power plant with additional Aalborg AV-6N boilers, Cengiz Enerji boosted steam cycle output by 40%.

Cengiz power plant 640x360