Heat Recovery Steam Generators & Waste Heat Recovery Units

Solutions in Heat Transfer Technology

NEM Energy Group is a leading OEM of Heat Recovery Steam Generators (HRSGs) and Waste Heat Recovery Units (WHRUs). With nearly a century of experience, NEM has supplied around 1,000 units worldwide, enough to power 200 million households. Headquartered in Zoeterwoude, Netherlands, NEM serves various industries, including power generation and energy storage. Specializing in heat transfer from waste heat, NEM focuses on gas turbine exhaust as a major source. We provide HRSGs for steam and WHRUs for non-steam applications across all markets.

Download the Heat Recovery Solutions brochure.

Fast Start & Cycling Operations

NEM is a worldwide provider of two types of Fast Start HRSG technologies: DrumPlus™ and Once-Through technology. NEM HRSG Fast Start solutions offer a quick response to power demand, while maintaining the lifetime of any HRSG. This ability is of special importance in so-called spot markets and locations where the daily fluctuation in power is aggravated by power fluctuations of renewables. NEM Fast Start solutions allow unrestricted gas turbine ramp-up which results in remarkable flexibility, reduced start-up costs, quick delivery to the grid and significantly lower CO and NOx emissions during start-up.

Modular Heat Recovery Systems

Flexible. Reliable. Cost-Effective.

NEM’s Modular Heat Recovery Systems are the solutions for gas turbines up to 100 MW. With a proven global track record, NEM’s modular Waste Hear Recovery Units (WHRUs) and Heat Recovery Steam Generators (HRSGs) are trusted across industries—onshore and offshore—offering faster installation, lower costs, and reliable performance.

Vertical Once Through Steam Generator
Ultra-Light OTSG
Vertical Drum Steam Generator
Horizontal Drum Steam Generator
Waste Heat Recovery Unit

Vertical Once Through Steam Generator

NEMs Vertical Once-Through design offers you fast start-up and shutdown capabilities. The small footprint makes it suitable for both onshore and offshore applications, like floating platforms. NEM can provide the Vertical OTSG in an Ultra-Light design, especially suitable for offshore applications, where we can integrate the unit in a gas
turbine and/or steam turbine module. It is capable of coping with lower fuel quality. When required, the HRSG can be designed with internal by-pass or for dry-running capability. The gas turbine continues operation and can be shut down later at any given moment.

NEM Vertical Once-Through HRSGs are excellent for industrial power applications, fast start and cycling operations. The design also offers the benefit of a very short construction time due to its modularity.

Abbreviation: OTSG
Gas Flow: VERTICAL

Design Once-Through Steam Generator NEM Energy product solution

Ultra-Light OTSG

For offshore applications NEM has a unique and patented ‘Ultra-Light’ design. Here the installation is designed as such to reduce weight to the optimal extend.

This results in the lowest total installed costs for our customers and allows customers in offshore areas to increase their gas turbine plant efficiency immensely.

This so called Ultra-Light design can be supplied for new gas turbine facilities for FPSO, FLNG or fixed rigs as well as to convert an existing offshore open cycle gas turbine to a combined cycle.

Abbreviation: UL-OTSG

Gas Flow: HORIZONTAL or VERTICAL

Ultra-Light Once-Through Steam Generator

Vertical Drum Steam Generator

Drum Type Steam Generator

We deliver various designs to fit your purpose, with a high degree of standardization in the pressure part modules. This enables a significant shorter overall lead time.

The concept results in lower installation costs, fewer site risks and potentially an earlier PAC for the complete plant.
The major advantages of the DTSG-concept can be summarized as follows:

Smaller footprint
Complete modular design
Faster construction time
Inclusion of SCR and duct burner without impacting footprint
Ideal for cogeneration applications

Abbreviation: DTSG
Gas Flow: VERTICAL

Design Drum Type Steam Generator NEM Energy product solution

Horizontal Drum Steam Generator

The horizontal drum design is custom-made and ideally suited for complex cogeneration projects. It offers several advantages over other configurations:

Short construction time
Reduced footprint
Proven, robust drum type design
No need for a condensate polisher, reducing system complexity and cost

Waste Heat Recovery Unit

The Waste Heat Recovery Unit (WHRU) range of NEM offers an efficient recovery method of thermal energy from gas turbine exhaust gases. The recovered thermal energy can be used for district heating, process heating or for the generation of electrical power via the NEM Heat ReCycle solution.

The WHRU is developed on the same design platform as the Vertical OTSG/DTSG which are used for steam generation. The WHRU can be used for the heating of various Heat Transfer Fluids (HTF’s) like glycol, thermal oil or other Organic fluids.

The WHRU can be equipped with duct burners and emissions reduction catalysts. Exhaust gas bypass systems can be installed outside or integral to the WHRU providing operating flexibility and smooth start-up.

Abbreviation: WHRU
Gas Flow: VERTICAL

Design Waste Heat Recovery Unit NEM Eneregy product solution

Large Heat Recovery Steam Generators

Robust. Future-Ready Design.

Proven in the field with hundreds of units installed and decades of expertise, NEM HRSGs offer the flexibility and performance needed today, while being the first certified for 100% hydrogen use in combined cycle plants.

We offer proven solutions for the largest gas turbines on the market(H- and J-class) regardless of OEM, including:

Horizontal Natural Circulation DrumPlus™
Vertical Once-Through
Horizontal Once-Through
Vertical Natural Circulation
Horizontal Natural Circulation

Horizontal Natural Circulation DrumPlus™

With NEM revolutionary DrumPlus™ Fast Start technology, no gas turbine start-up holds are required. The drum’s thin wall allows unrestricted ramp-up of the gas turbine.

The minimized thickness is a result of the small drum diameter. A key aspect is the external location of the water-/steam-separators, allowing an optimal separator design without the limits set by the confined space in the drum.

Our unique know-how has allowed us to develop a game-changing new design: the DrumPlus™, a drum-type Fast Start HRSG. This patented boiler technology is available for single-, double- and triple-pressure HRSGs. Two DrumPlus™ HRSGs were officially inaugurated at NRG’s Flex Plant™ 10, El Segundo, California in September 2013. This Fast Start boiler technology is the first of its kind in commercial operation, allowing the gas turbine to reach 150MW in a time span of just ten minutes!

NEM has now developed DrumPlus2.0 which results into the same operational flexibility as well as offering benefits during the installation period.

Abbreviation: HNC+
Gas Flow: HORIZONTAL

Design Horizontal Natural Circulation DrumPlus NEM Energy product solution

Vertical Once-Through

HRSGs have a significantly shorter start-up time than the regular drum-type HRSG. The high pressure part of the boiler is designed as a once-through system. As a result, the boiler is capable of starting up in a very short time; it is also suitable for advanced steam parameters and has a high degree of flexibility.

The intermediate and low pressure sections are equipped with steam drums and designed as a natural circulation system.

NEM is the only vertical HRSG supplier in the world. In the HRSG, water is converted into steam without the use of a drum. Instead, the water is transformed into superheated steam that can move through the tube bundles, depending on the heat input.

Besides fast start-up and high efficiency, one of the great benefits of a vertical-design is the overall small footprint and the short site construction time.

Abbreviation: VOT
Gas Flow: VERTICAL

Once-Through HRSG – technology is licensed to NEM by Siemens Energy

Design Vertical Once Through NEM Energy product solution

Horizontal Once-Through

In the HRSG, water is converted into steam without the use of a drum. Instead, the water is transformed into superheated steam that can move through the tube bundles, depending on the heat input.

Abbreviation: HOT
Gas Flow: HORIZONTAL

Once-Through HRSG – technology is licensed to NEM by Siemens Energy

Design Horizontal Once-Through NEM Energy product solution

Vertical Natural Circulation

NEM HRSG’s unrivalled state-of-the-art patented ‘counter flow’ evaporator design and proven experience with natural circulation provides the benefits:

Free expansion of headers and tubes
Easy access to headers and bends for inspection
Easy repair and maintenance
Easy construction at site
Suitable for heavy fuel oil applications

Abbreviation: VNC
Gas Flow: VERTICAL

Design Vertical Natural Circulation NEM Energy product solution

Horizontal Natural Circulation

These HRSGs have a horizontal exhaust gas path with the heat exchanger tube bundles arranged vertically. The units are designed for natural circulation of the water-steam mixture in the evaporator tubes. A ‘Once-Through’ design is also available.

The NEM horizontal HRSG features a so-called ‘cold-casing’ design. The casing is completely internally insulated and lined with sheeting, allowing thermal growth.

This cold-casing design allows a fast gas turbine start-up and is more suitable for the high gas temperatures associated with modern gas turbines and/or supplementary firing.

Abbreviation: HNC
Gas Flow: HORIZONTAL

Design Horizontal Natural Circulation NEM Energy product solution

Customer Benefits

We are a highly experienced boiler OEM with the widest variety of installed boiler designs worldwide.
We offer horizontal and vertical boilers for a gas turbine range from 10 MW up to the largest machines.
Our fast start solutions provide savings for your plant on both fuel costs and emissions.
For brown field application, we can design the boiler with a minimum downtime for your existing plant, minimizing the modifications required at the site.

NEM minimizes the environmental footprint and contributes to longterm profitable and sustainable business.
NEM executes projects all around the world. We are a strong partner, capable of helping you to develop your projects.
NEM can optimize the boiler design to perfectly suit the gas or steam turbine (or both).

Producing Cleaner and More Efficient Energy

Energy Transition

Heat Recovery Systems Projects

Sandow Lakes Ranch Project

USA
Keadby II Project

United Kingdom

Niels Veldkamp
Business Unit Director Heat Recovery Solutions

Are you interested in learning more about our Heat Recovery Solutions or exploring how we can support your energy projects? Feel free to get in touch, we’ll be happy to answer your questions and discuss the possibilities.

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