Steam generation

An efficient boost

Steam is an essential element in the energy supply system. As a primary energy source, it fulfils many important functions, whether it’s used to operate a turbine, as process steam for use in industry, or for district heating.   Especially in power plants, heat-recovery steam generators (HRSG) are valuable: They substantially increase a plant’s overall efficiency. This helps you counter the increasing cost of fuel. You also benefit from greater flexibility when operating at part load or during load changes.

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Once-through steam generators

Benson® technology

Benson technology is a proven process for large-scale steam generation in power plants. The heart of this process is the once-through principle. Combined with sliding pressure operation, this allows for highly efficient, flexible, and reliable power plant operation.

Superior technology for the latest power plant applications

Today combined cycle gas power plants need to be more efficient and flexible than ever, because they have to both

  • Cover peak loads and
  • Serve as backup reserves for renewables

This is where Benson HRSGs make an important contribution. They can be constructed either horizontally or vertically and will fit into any power plant architecture.


Benefits compared with drum-type steam generators

  • Steam parameters can be increased because there is no pressure limitation
  • Increased efficiency in part-load operation and at high ambient temperatures, thanks to reduced attemperator flows compared with a drum-type HRSG
  • Increasing operational flexibility: no limit on gas turbine load transients during startup and load changes, and no limit on load transients for possible duct firing

The first combined cycle power plant with a Benson heat-recovery steam generator (HRSG) – the 390-MW Cottam CDC, located in Great Britain – was successfully commissioned in 1999. More than 100 Benson heat-recovery steam generators have been commissioned to date or are currently under construction.

Supercritical pressure for maximum efficiency

The overall efficiency of a steam power plant counts in every respect, whether it’s reducing emissions or increasing economic efficiency. The best way to boost efficiency is by selecting high steam parameters. The once-through principle permits steam generation even at supercritical pressure. To date Benson boilers have been built for pressures up to 310 bar.


Contribution to flexible power plant operation

The Benson steam generator is especially well suited to flexible sliding-pressure operation: A steam power plant with a Benson steam generator can sustain load transients of four to six percent per minute over a wide power output range. High plant efficiency is ensured even at part load.


Sophisticated construction ­– individually optimized

Benson steam generators can be precisely adapted to suit your firing conditions: Different furnace sizes and geometries can be used depending on the fuel used. An important factor here is that the functions on the water/steam side are not restricted. Benson steam generators have been constructed with the broadest possible range of firing systems, including fluidized bed combustion.


Lately, the Benson steam generator with vertical rifled tubes has been successfully established in the market. Based on the Benson Low Mass Flux Design, this type of steam generator combines outstanding operating characteristics with low investment costs and high levels of reliability.


More than 1,300 Benson fired steam generators have been commissioned to date.

Start with something good – and make it even better

Benson steam generators have outstanding operating characteristics and are extremely reliable – thanks to continuous research and development. And we are refining the technology even more: We’re working intensively to optimize the heat transfer, pressure drop, and flow stability of two phase flows in evaporator tubes. Siemens has its own Benson test rig for the trials. The results of the trials have led to the creation of the world’s largest database on heat transfer and pressure drop in evaporator tubes, and support the development and validation of the Siemens Benson design software.


Another key area of focus is the development of Benson-specific control concepts, which make a key contribution to ensuring the best possible operation of your particular system.

Available worldwide

The Siemens Benson license is available for fired steam generators as well as for heat-recovery steam generators. It primarily addresses the thermodynamic and thermohydraulic design of the evaporator system in Benson steam generators. Basically, the license comprises the following components:

  • Use of Siemens patents for the construction of Benson steam generators
  • Use of specifically developed and highly specialized Benson design software
  • Training and consulting
  • Transfer of the latest findings from research and development

In addition to providing the Benson license, we also advise utilities on questions related to the evaporator system of once-through steam generators.


Licensees of Benson heat-recovery steam generators

Europe: AC Boilers S.p.A. (Italy), Amec Foster Wheeler Energía S.L.U. (Spain), CMI SA (Belgium), NEM Energy b.v. (Netherlands), STF S.p.A. (Italy)

Asia: BHI Co. Ltd. (Korea), Hansol SeenTec Co. Ltd. (Korea), IHI Corporation (Japan), GS Entec Corp. (Korea – Sublicense), S&T Corporation (Korea)

Americas: Innovative Steam Technologies (Canada), Nooter/Eriksen Inc. (USA), Vogt Power International Inc. (USA)


Licensees of fired Benson steam generators

Europe: AC Boilers S.p.A. (Italy), Amec Foster Wheeler Energia Oy (Finland), Burmeister & Wain Energy A/S (Denmark), Doosan Babcock Ltd. (Great Britian), Mitsubishi Hitachi Power Systems Europe GmbH (Germany), PJSC TKZ Krasny Kotelshchiik (Russia), Rafako S.A. (Poland)

Asia: Ansaldo Caldaie Boilers India Pvt. Ltd. (India), BHI Co. Ltd. (Korea – Sublicense), ISGEC Heavy Engineering Ltd. (India – Sublicense), Shanghai Boiler Works Co. Ltd. (China – Sublicense, restrictions to CFB boilers), Thermax Babcock & Wilcox Energy Solutions Pvt. Ltd. (India – Sublicense), Cethar Ltd. (India – restrictions to CFB boilers), Dongfang Boiler Group Co. Ltd. (China), Doosan Heavy Industries & Construction Co. Ltd. (Korea – Sublicense), Harbin Boiler Co. Ltd. (China – Sublicense), BGR Boilers Pvt. Ltd. (India – Sublicense)

Americas: Amec Foster Wheeler North America Corp. (USA), Babcock & Wilcox Power Generation Group (USA), Riley Power Inc. (USA)

Drum-type steam generator

Recirculating steam generation

Robust drum technology also makes it possible to use steam for basic applications – for electricity generation or supplying heat. An innovative drum design improves flexibility and efficiency in power plant operation.
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Give your power plant a boost

Does your power plant need to provide a flexible reserve? Or do you want to be able to extract heat? In both these cases, a steam generator is essential: and we’ll find the right technology for your needs.

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