Power plant products |
‘First-in-class pump technology’ for Keadby 2 CCGT
Built by SSE in collaboration with Siemens, the 840 MW Keadby 2 CC power station in Lincolnshire, UK, is one of the most advanced gas-fired power plants in the world. Scheduled to commence operation during 2022, the facility will be the first commercial deployment of the 50 Hz version of Siemens’ SGT-9000HL gas turbine. In response to a fast-changing energy market, the plant has been designed to offer high efficiency, flexibility, and reliability. Sulzer’s innovative pump technology is said to play a key part in this achieving this performance. To achieve its overall efficiency target of 63%, Keadby 2 is using a 1-1 design, a single gas turbine linked to a single steam turbine. The equipment and all critical ancillary components must be able to offer extremely high efficiency levels across a wide range of loads. The Keadby team decided to use Sulzer pumps, which it considered the most advanced technology available.
The plant will use two feedwater pumps, model MD200-400, which have been upgraded in collaboration with leading gas turbine manufacturers, including Siemens, specifically to meet the requirements of the new generation of H-class turbines. The pumps are set up in a 2x100% configuration, with one duty unit and the other on standby.
Patrick Welz, head of tendering EMEA for Sulzer, commented: “Thanks to their advanced hydraulic and mechanical design, [these] pumps will operate at an efficiency of more than 81%, requiring a rated power of only 5.1 MW to achieve suction and discharge flows of 860 m3/ hour and 730 m3/hour respectively”.
Hydraulic thrust balancing One key feature of the Sulzer pump is its hydraulic thrust balancing system, which includes a balance drum and thrust bearing that have
been developed for a long life under extreme operating conditions. Combined with bearings and a lubrication system that have both been optimised for the application, this greatly improves the ability of the pump to manage overrun situations where it may be required to operate outside its normal performance range. The balance drum and bearing arrangement is also said to help the feedwater pumps to achieve a high level of reliability and availability, with a longer service life and a lower requirement for maintenance than alternative designs. That is an especially important attribute for the Keadby 2 project, which will feature the first HL-class turbine in Europe to be operated under a 15-year long-term service contract.
Performance
Sulzer was also selected to deliver condensate extraction pumps and cooling water pumps as part of the same project. The condensate extraction pumps came from the SJD-CEP series of vertical pumps and are said to offer low net positive suction head (NPSH) as well as high head per stage and excellent efficiency figures. The cooling water pumps were selected from Sulzer’s SJT/SJM-CWP range, a fabricated pump that offers much lower weight and higher efficiency than equivalent cast iron designs.
Thermal stability
CCGT power stations such as Keadby 2 tend to be used for peak lopping and supply balancing duties, responding to peaks in demand or supply shortfall when output from renewable sources is reduced. That requirement leads to significant cycling and the resulting rapid changes in load and temperature.
With this in mind, the Sulzer design team paid particular attention to the thermal stability of the MD200-400, with the mass distribution
Above: Installed SJT CWP pump
in the suction and discharge casings optimised for thermal behaviour as well as castability. The pump’s stage casing is investment cast for improved thermal performance, and the tensioners that hold the casing together use a Sulzer patented design that provides additional security under cyclic operating conditions.
Turbine foundation design creates new home for marine life
Vattenfall, with Dutch nature conservation organisation De Rijke Noordzee, is carrying out a study to find out how the ‘nature inclusive’ design of turbine foundations can support marine life. The study is being performed at Hollandse Kust Zuid, the largest offshore wind farm in the world. Water channels in the wind turbine foundations offer an opportunity for fish and other marine species to enter and leave again. The study is aimed at finding out to what extent the interior spaces of the turbine foundations can be used by marine life to settle, shelter, and as a feeding ground, and is the first time that research of this kind has been carried out. The study being conducted at the Hollandse Kust Zuid wind farm,
which is located 18 to 34 km off the Dutch coast between the cities of The Hague and Zandvoort, also involves The Royal Netherlands Institute for Sea Research, NIOZ.
“If the results meet our expectations, this will boost marine biodiversity”, commented Erwin Coolen, programme director of De Rijke Noordzee. “Nature inclusive design is the future.” The ellipse-shaped openings measure approximately 30 cm by 1 m and are located above the seabed and just below the water surface. Over the next two years data will be collected regularly to check the development of biodiversity. Last winter, scientists from De Rijke Noordzee carried out their first series of
38 | May 2022|
www.modernpowersystems.com
measurements. Findings will be included in a toolbox called “Nature development in wind parks” that De Rijke Noordzee will develop. Its open-source character is intended to make it easy and cost-efficient to reuse in new projects. Gijs Nijsten, responsible for sustainability at Hollandse Kust Zuid, commented: “Offshore wind is growing rapidly and will continue to expand significantly over the next years. We are constantly looking for ways to minimise the impact our projects have on the ecosystem. Continuous innovation and modification of turbines has led to an ever improving balance between sustainable produced electricity and a healthy ecosystem.”
Above: Bareshaft pump SJT CWP
Above: Installed feedwater pump
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