Engineered Pump Solutions for Molten Salt Heat Transfer Systems
Concentrated Solar Power (CSP) plants place exceptionally high demands on pump technology. The use of molten salt as a high‑temperature heat transfer and thermal storage medium requires reliable, precisely engineered pump solutions to ensure safe and efficient plant operation.
Rheinhütte Pumpen provides engineered pump solutions for molten salt systems in CSP applications, supporting reliable energy generation and long‑term operation under extreme thermal conditions.
Process Requirements and Challenges
In CSP plants, molten salt is used as both a heat transfer fluid and thermal energy storage medium, enabling efficient power generation even without direct solar input. Typical operating temperatures range from 150 °C up to 600 °C.
From a pumping perspective, CSP molten salt systems involve:
- very high operating temperatures
- strong thermal cycling during start‑up and shutdown
- strict requirements to keep the salt fully molten
- thermal expansion and mechanical stress
- continuous 24/7 operation
These conditions require pump designs that go far beyond conventional industrial solutions.
Engineered Pump Solutions for CSP Molten Salt Systems
Rheinhütte Pumpen develops application‑specific pump solutions for molten salt circuits in CSP plants, primarily based on vertical pump designs optimized for high‑temperature operation.
Pump systems are tailored to:
- plant‑specific layouts
- operating temperature and pressure conditions
- thermal expansion behavior
- circulation and bypass concepts
This ensures stable performance and safe operation across all operating phases.
Material and Design Expertise
Reliable molten salt pumping depends on robust mechanical design combined with temperature‑resistant materials.
Rheinhütte Pumpen applies extensive expertise in:
- high‑temperature metallic materials
- corrosion‑ and wear‑resistant alloys
- design principles for thermal expansion compensation
Optimized hydraulics, mechanically stable constructions and suitable sealing concepts ensure long service life, high operational safety and stable pump performance in solar thermal applications.
Your Benefits with Rheinhütte Pumpen
- Pump solutions engineered specifically for CSP molten salt systems
- Reliable operation at temperatures up to 600 °C
- Designs adapted for thermal cycling and continuous operation
- Long service life and low total cost of ownership (TCO)
- Proven performance in solar thermal power plants worldwide
With decades of experience in high‑temperature pump engineering, Rheinhütte Pumpen is a trusted partner for efficient and reliable CSP molten salt applications.
Vertical Molten Salt Pump – Customer Benefits
Fact 1: Optimized Hydraulic Design
The discharge pipe for the full flow rate is completely separated from the column pipe and the pump main shaft.
Customer benefits:
- Undisturbed flow profile and constant flow velocity
- No hydraulic losses caused by bearing holders in the flow path
- Increased hydraulic efficiency
- Bearings can be dimensioned generously, allowing higher load capacity
- Reduced risk of bearing cracking during rapid temperature fluctuations
- Defined bearing lubrication, independent of differential pressure
- No dry‑running damage in case of interrupted flow
Fact 2: Safe Operation at Zero Flow
The separated discharge pipe design allows continuous pump operation at 0 m³/h, even with a closed discharge valve.
Fact 3: Flexible Discharge Nozzle Design
- Available in all required sizes
- DIN and ASME standards
- Customer‑specific gasket systems
- Allowable nozzle loads up to 2 × API standard values (higher on request)
Fact 4: Specialized Molten Salt Test Facility
A dedicated molten salt test facility has been in operation since 2016, enabling:
- Testing of vertical pumps with insertion lengths up to 20 m
- Full test supervision by customers and third‑party inspectors
- Reliable validation under realistic operating conditions
Fact 5: Sole Plates & Thermal Expansion Compensation
- Custom‑designed sole plates manufactured according to tank or vessel geometry
- Optional compensators for thermal decoupling between pump and tank
- Prevention of excessive forces and moments due to thermal expansion
- Especially beneficial for large pumps and high‑temperature applications
Fact 6: Dry and Low‑Pressure Shaft Sealing
- Pumped liquid does not reach the upper shaft seal during normal operation
- Robust stuffing‑box design with excellent MTBF values
- Shaft seal pressure limited to tank gas phase pressure
- Optional floating ring seal for reduced nitrogen consumption
Fact 7: Proven Pump Design & Longstanding Expertise
- Experience with molten nitrate salt pumping since the 1950s
- Company history dating back to 1857
- Continuous innovation and leadership in critical pump market segments
- Long‑term reliability for CSP applications (parabolic trough and power tower)
Fact 8: Scientifically Based Engineering Studies
- Thermal analyses of pump behavior in the tank
- Vibration and critical frequency studies
- State‑of‑the‑art FEM simulations for maximum operational safety
