Sulzer secures contract for major concentrated solar power project in China

In a significant step towards renewable energy sources, Sulzer has been selected to supply hot and cold molten salt pumps for a major solar power plant (CSP) tower project in China.

The planned 100 MW site is part of an ambitious program driven by growing demand for sustainable energy sources in China and around the world. Sulzer’s expertise in this sector has enabled the implementation of numerous successful projects that can provide solar energy around the clock.

Molten salts, used in the nuclear industry for almost 70 years, have led Sulzer to design and manufacture pumps for transferring high-temperature fluids around cooling circuits. The company pioneered the technology for the solar industry more than 15 years ago, enabling night-time thermal storage.

The process involves pumping molten salt into solar collectors, where its temperature is increased from around 300°C to 600°C. The heated salt is then stored in a tank and sent to a heat exchanger, where the heat energy generates steam to power a turbine/generator. This circuit acts as a thermal battery, allowing solar power plants to continuously provide energy under optimal solar conditions.

Sulzer has a long history of supplying molten salt pumps to solar installations around the world, including recent projects in China. The 100 MW CSP tower project is the first of its kind to use Sulzer pumps for both hot and cold circuits. Three cold molten salt pumps, equipped with 2.6 MW motors, will extend 18 meters below the baseplate into the cold molten salt tank, complemented by two hot pumps. All pumps will be manufactured at Sulzer’s Suzhou facility.

One significant challenge was the increased operating pressure required in the molten salt circuits. Smaller sites typically operate at around 50 bar, but this project required a supply pressure of 100 bar. Each pump was custom built to cope with the higher pressure and slightly greater power requirements. Key aspects such as the design of the throttle sleeve and sleeve bearings were meticulously assessed, designed and tested before production began.

The end user wanted to achieve several goals, including acquiring key equipment from international brands, preferably manufactured in China, while maintaining cost-effectiveness. Sulzer met all these goals, with the bare shaft pump engineering completed in Europe and production undertaken jointly in Belgium and China. In addition, Sulzer offers a comprehensive support package through a local service centre, streamlining spare parts inventory for the end user.

Local Sulzer engineers will support the installation and commissioning of the equipment. Given their length, the pumps will be assembled on site before installation in the storage tanks.

The installation follows several other successful projects implemented by Sulzer in China, including three hot pumps for another 100 MW CSP power plant and six hot pumps and five cold pumps for a 42 MW parabolic trough plant.

The 100 MW CSP tower project demonstrates Sulzer’s commitment to developing renewable energy technologies and ensuring a sustainable and reliable energy future.