How to choose a high temperature molten salt pump? Temperature, Flow, Materials & Reliability Buying Guide

Why Are Standard Centrifugal Pumps Not Suitable for High-Temperature Molten Salt Systems?

As a high-temperature heat transfer medium, molten salt typically operates at temperatures ranging from 300℃ to 600℃ or even higher. It also has characteristics such as solidification risk and unique corrosion behavior.

When standard centrifugal pumps are used in such operating conditions, several problems may occur:

1. Thermal Expansion Causing Operational Instability

During long-term high-temperature operation, the pump casing, shaft, and internal components undergo thermal expansion.

Without proper thermal expansion compensation design, the following issues may occur:

• Rotor misalignment;

• Changes in impeller clearance;

• Increased vibration;

• Bearing damage.

Therefore, high-temperature molten salt pumps require dedicated designs to ensure stable operation under extreme temperature conditions.

2. Molten Salt Solidification Affecting Startup Reliability

When the temperature decreases, molten salt may crystallize or solidify. If the residual molten salt inside the pump chamber is not maintained above the required temperature after shutdown, it may result in:

• Startup failure;

• Impeller seizure;

• Damage to internal components.

In practical engineering applications, insulation systems, heat tracing systems, and temperature control strategies during startup and shutdown are commonly adopted to ensure reliable operation.

Key Technical Parameters for Selecting High-Temperature Molten Salt Pumps

High-temperature molten salt pump selection should not be based only on the pump model. It requires comprehensive analysis according to actual process conditions and operating requirements.

The main selection parameters include:

Flow Rate Selection

Flow rate determines the circulation capacity of the molten salt system and should be determined based on heat exchanger requirements, thermal storage capacity, and process circulation demand.

Long-term operation away from the design flow range may result in:

• Reduced efficiency;

• Increased energy consumption;

• Higher vibration levels.

During procurement, customers are recommended to provide:

• Normal operating flow rate;

• Maximum flow rate;

• Minimum circulation flow rate.

Head Selection

Pump head is mainly required to overcome:

• Pipeline pressure losses;

• Heat exchanger resistance;

• Valve resistance;

• Static elevation difference.

Excessive head selection may increase motor power requirements and overall system operating costs.

Operating Temperature Selection

Operating temperature is one of the most critical factors affecting molten salt pump design. Different temperature ranges directly influence:

• Pump casing materials;

• Bearing configuration;

• Sealing arrangement;

• Cooling design.

For example:

• 300–400℃: Conventional industrial molten salt systems;

• 400–550℃: Concentrated solar thermal energy storage systems;

• Above 550℃: High-temperature energy storage and special industrial applications.

Key Factors in High-Temperature Molten Salt Pump Selection

1. Pump Configuration

High-temperature molten salt pumps commonly adopt vertical long-shaft structures in engineering applications.

Main features:

• Pump casing and hydraulic components are immersed inside the molten salt tank;

• Stable suction performance;

• Reduced cavitation risk;

• Suitable for large-scale circulation systems.

Main applications include:

• Concentrated Solar Power (CSP) projects;

• Molten salt energy storage systems;

• Industrial heat transfer systems.

2. High-Temperature and Corrosion-Resistant Material Selection

Material selection should consider:

• High-temperature strength;

• Oxidation resistance;

• Thermal fatigue performance;

• Molten salt compatibility.

Common materials include:

• Stainless steel;

• High-temperature alloys;

• Special heat-resistant alloys.

3. Rotor and Bearing Stability Design

Reliable design should ensure:

• Rotor concentricity;

• Axial stability;

• Low-vibration operation;

• Long-term continuous operation capability.

Main Application Fields of High-Temperature Molten Salt Pumps

Concentrated Solar Power (CSP)

Molten salt is used for:

• Thermal energy storage;

• Heat transfer;

• Steam generation.

Molten salt pumps must operate continuously under high-temperature conditions, requiring extremely high equipment reliability.

Molten Salt Energy Storage Systems

Main applications include:

• Industrial waste heat recovery;

• Grid peak shaving;

• High-temperature energy management.

Chemical Heat Transfer Systems

Molten salt is widely used for:

• High-temperature reaction heating;

• Precise temperature control;

• Continuous production processes.

Frequently Asked Questions About High-Temperature Molten Salt Pump Procurement

What Information Is Required for Pump Selection?

Customers should provide the following technical information:

• Molten salt type;

• Operating temperature;

• Flow rate;

• Head;

• Density and viscosity;

• Installation configuration;

• Continuous operating duration.

Why Do Different Manufacturers Offer Significantly Different Prices?

High-temperature molten salt pumps are not standard products. Price differences mainly come from:

• Material grades;

• Structural design;

• Manufacturing processes;

• Testing capabilities;

• Project experience.

Low-cost solutions may not meet long-term high-temperature operating requirements.

Jiangsu Feiyue Pump Industry High-Temperature Molten Salt Pump Solutions

Jiangsu Feiyue Pump Industry provides customized molten salt pump solutions for renewable energy, chemical industries, and high-temperature industrial applications based on actual operating conditions.

The solution services include:

• Operating condition analysis;

• Flow, head, and temperature matching;

• High-temperature structural design;

• Material selection;

• Customized manufacturing;

• Performance testing.

The key consideration in high-temperature molten salt pump selection is not the lowest purchase price, but long-term reliable operation capability.

Selecting a manufacturer with strong engineering design expertise and manufacturing experience can reduce operational risks and improve system safety, stability, and reliability.