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Heat Recovery Steam Generators – HRSGs

The industry leader in custom-designed Heat Recovery Steam Generators (HRSGs).

World Leader in Heat Recovery Steam Generators

With more than 1,000 HRSGs in operation around the world, Nooter/Eriksen has led the way in developing heat recovery technology behind combustion turbines as the equipment has grown in size and complexity. Innovative solutions are provided to meet the thermal performance, sound, and emissions requirements of your projects. We have the experience and expertise to design to a large variety of international codes and standards (e.g. EN, METI, ASME). Nooter/Eriksen HRSGs are designed to address concerns of shipping restrictions, total installed costs (field constructability), reliability, and maintainability.

Drum Type

Nooter/Eriksen Heat Recovery Steam Generators (HRSGs) are custom-designed to meet your project-specific needs. Our primary offering is a natural circulation design with horizontal exhaust flow and vertical tube design with internally insulated casing and structure, but we can also provide vertical solutions, when needed.

Heat Recovery Steam Generator (HRSG)

Once Through Steam Generators

Once Through Steam Generators (OTSGs) are under a license from Siemens AG Agreement that utilizes two single pass evaporator stages to evaporate and partially superheat the steam flow in the once through evaporator section.

The primary stage evaporates the water to an intermediate steam quality and the secondary stage completes the evaporation and superheats the steam to a minimum level. Outside of the actual evaporator design, the HRSG and the OTSG are identical (though the actual heating surfaces may vary somewhat).

Once Through Steam Generator



Nooter/Eriksen has dedicated extensive time and effort developing a multitude of solutions to meet the thermal performance, sound, and emissions requirements of your projects.


Nooter/Eriksen designs within shipping limitations while minimizing field construction hours. Options are available to further maximize shop fabrication.

Simple Cycle Applications

Today’s market is requiring peaking units providing fast power gradients when high demand has to be met in a very short time. Normally these units are operating for just few hundreds hours per year but at a very remunerative power selling price. For this reason the plant efficiency is not as important as the capital cost, so many time a simple cycle composed by only a gas turbine fits the needs. The gas turbine exhaust as such, even with low NOx burners are not meeting the emission requirements and the relevant pollutants have to be removed before their release in the atmosphere. SCR and CO Catalyst Systems operate at lower temperature and thus the exhaust have to be cooled before entering in the emission abatement equipment. Nooter/Eriksen can supply the entire exhaust treatment system composed of:

  • Fresh air fans
  • Heat exchangers
  • Ductwork and stack
  • Highly modularized Hot/Warm/Cold Catalyst designs with fast start capability.

Sizes from 40MW to the most advanced class combustion turbines natural gas or ultra-low diesel fuel fired.